PASADENA – From the foul-smelling, belching black maw of the La Brea Tar Pits have come the bones of ancient beasts – and from these, a new understanding about condor history.

Caltech undergraduate Valerie Syverson has found that the California condor once likely co-existed with a separate condor species – one even larger than the avian giants still alive today.

“She looked at just about all the common elements of the wings and the legs and the skull,” said Donald Prothero, her advisor and an Occidental College paleontologist. “Sure enough, when you measure enough specimens and you plot them, boy they sure stand out like night and day.”

The ancient condors, the team found, had longer, narrower skulls and were about 10 percent to 20 percent larger than their modern relatives which, with 9-foot-wide wingspans, are no small potatoes themselves.

“The tar pits are one of the richest Ice Age fossil sites in the world,” said John Harris, chief curator of the George C. Page Museum at the tar pits. “They’re important not only because of the diversity, but because the fossils are very well preserved.”

In particular, the pits are a gold mine for the bones of ancient scavengers like the condors.

“One trapped horse may result in a couple of saber-toothed cats and some dire wolves,” Harris said.

The Page Museum’s collection contains thousands of the long-legged bones of birds of prey whose feet were caught by the dark morass.

Because the tar pits ensnared creatures between 9,000 and 40,000 years ago – a period encompassing an entire ice age – the cache proved an ideal location for Prothero and his students to study how climate change affected animal species.

Their work, Prothero said, suggests none of the animals changed in size because of the shifting temperatures.

But it also had the added benefit of answering a long-standing question about the California condor’s past, showing they are a species all their own, rather than direct descendents of the larger Ice Age birds.

In the near future, Prothero said, he plans to study ancient condor remains from other collections to learn if the La Brea species has been named before or is new – a prospect he considers likely.

Whatever he finds, though, the condors won’t be biggest bird to have tangled with La Brea’s sticky depths.

That honor, Harris said, goes to a bird called Merriam’s teratorn, which had a wingspan of 12 feet.